arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1405.7486astro-ph.SRastro-ph.EP
收藏

低质量恒星宜居带的演化。详细的恒星模型和不同质量和化学成分的分析关系

Evolution of the habitable zone of low-mass stars. Detailed stellar models and analytical relationships for different masses and chemical compositions

G. Valle, M. Dell'Omodarme, P. G. Prada Moroni, S. Degl'Innocenti

备注：
Accepted for publication in A&A, abstract abridged
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

我们研究的时间演化的宜居带（HZ）的低质量恒星-只由于恒星演化-并评估相关的不确定性。然后将这些不确定性与采用不同气候模式的不确定性进行比较。我们计算了质量在[0.70 - 1.10] Msun范围内、金属丰度Z在[0.005 - 0.04]范围内以及不同初始氦含量的恒星从主序前阶段到红巨星分支尖端氦闪光的演化轨迹。我们评估了几个特性的HZ，如从主机恒星的距离，在那里的可居住性是最长的，这种可居住性的持续时间，该区域的宽度，可居住性持续的最大值的一半，和边界的连续宜居带（CHZ）的可居住性持续至少4 Gyr。我们开发了分析模型，精确到百分比水平或更低，这使得可以获得这些特性依赖于主机恒星的质量和化学成分。主恒星的金属丰度在确定HZ中起着相关的作用。初始氦含量占CHZ边界的变化高达30%和10%的内部和外部边界。计算的分析模型允许的CHZ边界的变化，这是由估计值的质量和金属丰度的宿主恒星的不确定性引起的第一次系统的研究。结果表明，CHZ内边界的不确定性约为30%，外边界的不确定性约为15%，这些不确定性大于基于最近修订的气候模式的不确定性，导致CHZ边界相对于参考情景的不确定性变化在5%以内。我们做了一个在线工具，提供HZ特性和插值恒星轨迹。

英文摘要：

We study the temporal evolution of the habitable zone (HZ) of low-mass stars - only due to stellar evolution - and evaluate the related uncertainties. These uncertainties are then compared with those due to the adoption of different climate models. We computed stellar evolutionary tracks from the pre-main sequence phase to the helium flash at the red-giant branch tip for stars with masses in the range [0.70 - 1.10] Msun, metallicity Z in the range [0.005 - 0.04], and various initial helium contents. We evaluated several characteristics of the HZ, such as the distance from the host star at which the habitability is longest, the duration of this habitability, the width of the zone for which the habitability lasts one half of the maximum, and the boundaries of the continuously habitable zone (CHZ) for which the habitability lasts at least 4 Gyr. We developed analytical models, accurate to the percent level or lower, which allowed to obtain these characteristics in dependence on the mass and the chemical composition of the host star. The metallicity of the host star plays a relevant role in determining the HZ. The initial helium content accounts for a variation of the CHZ boundaries as large as 30% and 10% in the inner and outer border. The computed analytical models allow the first systematic study of the variability of the CHZ boundaries that is caused by the uncertainty in the estimated values of mass and metallicity of the host star. An uncertainty range of about 30% in the inner boundary and 15% in the outer one were found. We also verified that these uncertainties are larger than that due to relying on recently revised climatic models, which leads to a CHZ boundaries shift within 5% with respect to those of our reference scenario. We made an on-line tool available that provides both HZ characteristics and interpolated stellar tracks.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

↑